Drinking water quality in Tafila province (south Jordan) was investigated by measuring some water quality parameters. Samples from 53 storage tanks at different sites in the province were collected and subjected to physical and chemical analysis including measurements of temperature, pH, electrical conductivity, total dissolved solids, total hardness, alkalinity and the concentration of calcium, magnesium, sodium, potassium, chloride, nitrate and sulfate ions. Langelier saturation index (LSI) and Ryznar stability index (RSI) were calculated for all samples. All LSI values were negative and lie within the range of -2.04 to -0.13 showing corrosive tendency of water in the province. LSI results are compatible with RSI results which showed values varying from 7.73 to 10.13.